Corals constitute colonies of animals and plants from the marine world, harboring extraordinary biodiversity and productivity. The world has always been fascinated by its variety of colors and its multiple amazing shapes.
However, sad and worrying news for the entire planet is that these corals are turning white, that is, they are dying at an alarming rate. Of the 1400 known coral species, 231 are at varying degrees of extinction risk. Ten years ago this number was only 13. As a result, the more than 2 million species sheltered by them also suffer the consequences and may even disappear.
But what is causing this? The answer is simple and much commented on nowadays: o global warming.
Corals are directly affected by temperature, solar radiation and ocean chemistry.
The waters of the seas are getting warmer, with this the corals contract and begin to suffocate the algae inside them. These, in turn, release toxins to force the coral to expel them. That's why they get sick and white. If the sea temperature doesn't return to normal, they eventually die.
In addition to being warmer, the seas are more acidic. With the increase in pollution, especially the increase in the concentration of carbon dioxide (CO2) in the atmosphere, the ocean ends up absorbing these gases. Diluted in water, carbonic acid is then formed, according to the reaction:
CO2(g) + H2O(1) → H2CO3(aq)
This affects corals because the acid "scavenges" the carbonates from the water that serve to calcify the coral skeleton. The carbonates (CO32-) react with acids releasing more carbon dioxide.
Corals are not the only ones affected, but mainly crustaceans such as oysters, mussels and crabs that have their shells corroded. Limestone plankton also suffer from this and, since they are in the marine food chain, serving as food for larger organisms, an imbalance will occur in the entire chain, including in species that feed the being. human.
It's an inevitable chemical process. Therefore, urgent measures must be taken. One example is Australia, which established coral areas to be protected from visitors and started to control the use of fertilizers on nearby plantations.
By Jennifer Fogaça
Graduated in Chemistry
Brazil School Team
Source: Brazil School - https://brasilescola.uol.com.br/quimica/cemiterio-corais.htm